In the case of a U-shaped relay yoke, in which a base (i.e., horizontal flange) of the yoke simultaneously forms the coil core, the coil former cannot be slipped horizontally onto the base of the U-shaped core after winding. Known solutions comprise a coil former which is fitted perpendicularly. A disadvantage thereof is that the coil former has to be pushed over the pole faces used for armature coupling, whereby particles may become deposited on these pole faces and impair functioning of the magnet system. Another solution consists in dividing the yoke at the base and giving it a two-piece construction, such that the coil former may be fitted onto the base after winding. A disadvantage of this solution is that the joint of the two-piece core may lead to an increase in magnetic resistance and thus to magnetic circuit losses.
An object of the present invention consists in avoiding the disadvantages of the prior art and providing a coil former for an electromagnetic actuator which may be fitted without difficulty directly to the base of the yoke.